Its possible to remove into two originial parts; but after 30 plus years of road grim etc; seem the only way is to saw-all with a metal blade. Theres a roll guide / connector rod that holds and supports the two mounts. That's the only succesful way ; that I know, for which i recently help a fellow member remove one. I recommend purchasing new mounts if funds are avaiable.
Sorry I don't hold a solid answer....

Mitch